The Kalkaska County prosecutor plans to drop charges on Monday, Peterson's attorneys said. A judge earlier found “clear and convincing” evidence that Peterson would not be convicted if retried with the new DNA evidence available.

In a statement issued by Northwestern’s Center on Wrongful Convictions, Plummer said Peterson “had no involvement. He knows nothing about it. The tragedy of this heinous crime was compounded by the wrongful conviction of an innocent man.”

Peterson, a Davison resident, was convicted after he provided false confessions four months after Geraldine Montgomery was raped and killed in her Kalkaska home. Testing excluded Peterson as the source of DNA found on the victim’s body, but prosecutors argued at trial that DNA found on the victim’s shirt collar, which couldn’t be tested, was likely his.

Tests now show that all of the DNA samples came from Jason Ryan, who was arrested last fall and awaits trial, Northwestern’s statement said. State police found no credible evidence the two men knew each other.

The wrongful-conviction groups say false confessions are not uncommon, particularly among the “young and cognitively impaired.”

David Moran, director of the Michigan Innocence Clinic, said police “agencies need to ensure that their officers get training not just on how to interrogate, but on how to identify and prevent false confessions.”

State Department of Corrections records say Peterson was discharged on Aug. 19.